I've noticed that heading west by itself regardless of temp changes still changes flight patterns.
I shot about 60 rounds each over the course of a month from my 7RM and 300RUM before I headed to WY and CO for antelope, mulie, and elk. The bullets were very consistent here. I made drop charts and taped them to the rifles.
We got to WY the day before our antelope season opened and shot our rifles for about 3-4 hours (includes MLs). My charts were trashed. The 150 Btip from the 7mag used to be 5" low at 300 with a 1" high at 100 sight in. However, in WY, it shot flatter. In fact, I popped of the first several rounds starting at 300 yards expecting them to hit between 3 and 7" low, but they were now only 1" low. I backed the target up to 100 and it was 2.5" high. This occurred on a Saturday. I shot the rifle on Thursday before we left.
Just about the same scenario with the 300RUM and 200AB.
The temperatures were roughly within 10 degrees (Casper, WY, vs. Crittendon, KY.)
The 300 rounds actually tightened up even more out west, where the 7mag 150's spread another 1" at 300.
It is rather frustrating but it is why I typically like to get to my destination 1-2 days prior to my season, so I can shoot and potentially redo a drop chart.
Becuase of the new powders that are available, that old rule of thumb really doesn't apply. Also, steel expands 1,000,000th of an inch for each one degree increase in temperature, assiting in making no two trajectories identical. One more thing, <font color="blue"> Stainless Steel Barrels </font> <font color="red"> are Not </font> recommended for shooting in freezing temperature conditions.
I finally got free and went hunting today up in the Paw Paw Bends.
When I dialed in my gun in August it was about 80 degrees. Today was about 40 degrees. I kept about five cartridges in the pocket of my Tee shirt which was underneath many other layers. About Noon I got bored sitting there watching a hillside with no deer on it so I decided to check my dial in. I found a big rock at 796 yards and got the gun all set and ready to go and then I reached inside my clothes and got a toasty warm cartridge and quickly slide it into the chamber and fired. Bullet struck maybe two inches below the aiming point with a wind drift of 18 inches. Thought about that a little while and decided to see if I could do it again. Got everything ready to go and reached inside my shirts and coats and got out another warm cartridge. Quickly fired that with exact same result - maybe two inches low. At 800 yds, me and this gun would normally shoot about a 5-6 inch group so when both bullets were within two inches of the aiming point elevation wise(the wind was really nasty -swirling and gusting), I was happy. My August dial in was still good with warm bullets. I had some cold bullets but it didn't occur to me to shoot them to compare with the warm bullets.
After the deer saw how deadly I was with smacking that rock, none would venture out into the open so I came home empty handed.
Glad you got to go for a while buffalobob. I'm still getting used to this zeiss scope. The cross hairs in this thing are like 1.5" drain pipe. I shot 2 small does yesterday afternoon at 290 yards, and 10 minutes later missed an easy 295 yard shot at a monster. I got in a hurry and pulled the shot I think, may have struck some limbs. He was checking a scrape on the field edge, and licking the branch over his head. All I could see were big long tines waving all around, so I put it on his shoulder and shot, but missed. Shot too fast I guess. You may have heard some of my profanity from your side of the bay. Gonna pour some tinks in his scrape and see if he comes out tonight.
7mm What? What's that stand for?
Not recommended by who? Why not? All my serious hunting rifles are sporting stainless barrels for their weather resistance.
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Me too. I have shot stainless steel barrels in 10 to 20 degrees below zero, meaning my rifle has been outside all night in sub zero temps before firing on more than one occasion.
I am not saying anybody is wrong. I would just like a little further information and preferably some proof. I am all ears.
Long range shooting is a process that ends with a result. Once you start to focus on the result (how bad your last shot was, how big the group is going to be, what your buck will score, what your match score is, what place you are in...) then you loose the capacity to focus on the process.